5. Mow your lawn efficiently - use math!

This is a fun article from Australia's The Age newspaper. It describes how you can use geometry to optimize your effort.

A Victa-ry for mathematics [no longer available]

6. Puzzles

Last mail I posed the question "Can you use five 5s to make 100?".

Here's one possible solution:

(5 - 5/5) × 5 × 5 = 100

Did you get any other answers?

Here's a new one:

"My husband's age," remarked a lady the other day, "is represented by the figures of my own age reversed. He is my senior, and the difference between our ages is one-eleventh of their sum." How old are they?

7. Final Thought: Greatness

The world's best discoveries were made along a road littered with wrong turns, insufficient knowledge and many outright failures. Don't worry if you feel like that in math class sometimes!

If at first you don't succeed, you're like everyone else who went on to greatness. [Patrick Combs]

Well sir, i like very much what you write in the final thoughts. You think great.... Even if i am very busy, i see your final thoughts and get inspired from the quotes of the great people. Long live. Hope you will continue this...

Dear sir, I am in need of solution of a mathematical solution of a problem in calculus.Please help me . Problem : To find the total length of a flat spiral having outer end radius= 15.5 units, inner radius=5 units & the increase in radius per turn=0.81 unit, the total No. of turns in the spiral is 7.5 . Thank you .

Goodevening dear sir.I am greatful with you,you write me continuously math articles.Which are important to learn mathematics.I hope i will receive such precious articles continuously in coming days.Once again i want to give you many thanks.

Puzzle of the ages of a couple:
I tried to solve the puzzle mechanically as under.

Let the two digits of their ages be 'a' and 'b'. Then 10a+b is the age of one of them and 10b+a is the age of the other.

The sum of the ages of the two =(10a+b)+(10b+a)=11a + 11b
The difference between the ages =(10a+b)-(10b+a)= 9a - 9b

11(9a-9b)=11a+11b
9a-9b = a+b (Dividing both sides by 11)
8a=10b
4a=5b a:b =5:4.
It is evident from the puzzle that the ages are of two digits and the only possible ages in the above ratio are 54 and 45